Soil Temps

Soil temperatures across the state at 6 inches deep, according to the Minnesota Runoff Risk Advisory Forecast as of Oct. 29. Map can be found at mnag.maps.arcgis.com.

WASECA, Minn. – Farmers are going full force to finish harvest while nature cooperates. Dryer weather, good field conditions and cool temperatures allowed for progress in all areas of fall fieldwork.

“The latter half of Oct. was certainly a lot better than the first half,” said Thomas Hoverstad, scientist with the University of Minnesota Southern Research and Outreach Center during a recent phone interview. “I would say soybean harvest is pretty well done now. Corn harvest, we are definitely coming on the homestretch.”

According to the USDA Crop Conditions and Progress Report, as of Oct. 28, only 13 percent of the soybean crop was left to be harvested. It is four days behind last year and a full week behind the five-year average.

On the corn side, harvest is just over halfway done at 58 percent complete, which is equal to the five-year average and one week ahead of last year. The USDA reports grain moisture dropping slightly, 1 percentage point, from last week to an average of 19 percent.

“Corn yields are all over the board,” said Hoverstad. “There were some fields where stalk integrity was an issue and winds were a big problem, we had quite a bit of corn broke over.”

Downed corn definitely creates challenges during harvest and impacts yield, but it also poses a challenge in the coming spring when the volunteer corn starts to grow in the next crop.

“Being aware that volunteer corn is the main thing and going after it when it is small,” he said. “There are a number of products that are very strong against volunteer corn in soybeans, so it is not a difficult solution, just need to recognize that it's out there.”

As growers make their way through the final steps of fall fieldwork, it is important to take note of where volunteer corn might be an issue in 2019. That way it can be addressed and resolved immediately.

Due to the cooler, dry weather, growers are moving quickly into those final steps. The USDA reports stalk chopping and baling happening the week ending Oct. 28. With 4.9 days suitable for fieldwork, there was also fertilizer and manure being applied as was fall tillage.

“Our long-term history shows that the last week of Oct. is about when soils reach 50 degrees and they usually don't come back over that,” he said. “Where it is the best management practice, fall anhydrous would be okay from here on out.”

The 50-degree mark is not only for anhydrous applications. It is best for any fall applied nitrogen for soil temperatures to remain below 50 degrees. At that cooler temperature, the soil microorganisms have slowed down and are not going to be converting the nitrogen to a form that can be lost.

According to the Minnesota Department of Agriculture’s Runoff Risk Advisory tool, as of Oct. 29, soil temperatures across the state at a 6-inch depth ranged from 45-50 in the southern portion of the state. More central Minnesota has soil temperatures ranging from 40-45 degrees and in the north, 35-40 degrees.

Depending on the soil type, fall tillage marks the final step in field work for the year.

“On our heavy glacial till or clay loam soils, definitely fall tillage is the best option for those that are doing tillage,” said Hoverstad.

Heavy soils hold moisture and are usually wetter in the spring. If the primary tillage is done in the spring on these fields, the soil structure just is not where it needs to be for a good seed bed.

“There is secondary tillage that we may need to do in the spring, but that's usually shallower and does not incorporate so much moisture,” he said.

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